Thanks both.
My Humax Forum » Freeview HD » FVP 4000T, 5000T
Question: "How do they tell the PVR to record"?
(17 posts)-
| Thu 16 Nov 2017 17:17:16 #11 |
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uk1 - 3 hours ago »
So the EPG is actually quite fluid and is kept constantly up to date. So a pragramme originally planned due to start at say 5pm might be updated to start at say 4.59pm or 5.01pm?There is the epg as in what is seen in the full guide and there is the now/next epg which, as Graham says, is what most models use when displaying now and next, plus is also used for the current and next programme in the full guide, at least for those boxes that have been freeview compliant (since about 2005?).
The now and next epg is very fluid for some channels and are updated in close to real time for what is playing out 'now'. While for other channels there are no real time updates.
In your example if a BBC TV progamme scheduled for 5pm is about to start being played out to start at 17:01:30 then the BBC appear to be sending the change to the 'now' at source about 20 seconds before that at 17:01:10. This allows for time for the epg in the TV data streams to be updated and the PVR to act on it. The epg for the channels in a particular multiplex are transmitted every 2 seconds while channel from the same transmitter but a different multiplex are transmitted every 5 seconds. PVRs that use a spare tuner to look for a 'now' to record are therefore at an advantage of they look at the epg from the multiplex that has the next wanted programme to record.The original expectation was that for those channels that don't update the 'now' in close to real time and still populate the full epg with times rounded to the nearest 5 minutes, would default the now and next epg (provided in advance by the channel's schedule provider) to an estimate likely to be slightly more accurate than the full epg.
If you want to see some technical detail behind this you could start off with section 8.10.1 from version 7 of the d-book. It is an old version of the d-book from 2011 but this side of things is still pertinent toady, plus that version of the d-book has been available since April 2015 via wikileaks. Search for 'D-Book 7 Part A v 1 wikileaks'.
The d-book also has references to supporting standards.| Thu 16 Nov 2017 21:27:36 #12 | -
Luke, thanks for that very clear explanation which explains a lot about how it works and it's potential. I guess that theoretically in the event that a new channel wanting to join the core channels for say purely recording, then this technology would offer them the opportunity to have a two tier service. One service could be with adverts and the other could be a service perhaps for a few pound a month a service that stops recording at the start of adverts and restarts recording at the end of adverts.
| Thu 16 Nov 2017 23:27:52 #13 | -
uk1 - 10 hours ago »
Luke, thanks for that very clear explanation which explains a lot about how it works and it's potential. I guess that theoretically in the event that a new channel wanting to join the core channels for say purely recording, then this technology would offer them the opportunity to have a two tier service. One service could be with adverts and the other could be a service perhaps for a few pound a month a service that stops recording at the start of adverts and restarts recording at the end of adverts.I can't see that happening you would need to incorporate additional codes for each ad break and the capability in the pvr software to pause and unpause recording. Most likely a whole new pvr.
| Fri 17 Nov 2017 9:55:15 #14 | -
grahamlthompson - 2 minutes ago »
Itv signal the switch from one programme to the next in the middle of the ads. The broadcaster would have to transmit two versions of the programme otherwise there would be a blank period in every ad break.I think what is being suggested is a special service for PVR users (financed by subscription) where an additional signal is sent to flag the start and end of advertisement breaks and the PVR would not record those segments. I think it is theoretically possible but so fraught with problems that I can't see it happening.
| Fri 17 Nov 2017 10:01:00 #15 | -
Martin Liddle - 17 minutes ago »
grahamlthompson - 2 minutes ago »
Itv signal the switch from one programme to the next in the middle of the ads. The broadcaster would have to transmit two versions of the programme otherwise there would be a blank period in every ad break.I think what is being suggested is a special service for PVR users (financed by subscription) where an additional signal is sent to flag the start and end of advertisement breaks and the PVR would not record those segments. I think it is theoretically possible but so fraught with problems that I can't see it happening.
I realised that but afaik the capability for a broadcaster to pause recordings doesn't exist. Having to break up a single event into multiple and unknown number of seperate sub recordings and seamlessly combine them into one recordings sounds horrendously complex to me.
What's wrong with the programmeable forward and reverse skip keys that allow ads in recording to be skipped in seconds ?
| Fri 17 Nov 2017 10:22:20 #16 | -
Thanks ...... nothing wrong at all. My question was hypathetical as you don't know what it possible until you know what is possible.
| Fri 17 Nov 2017 10:32:37 #17 |
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